match case 的用法
package matchcase
object matchcase01 {
def main(args: Array[String]): Unit = {
println(getProvinceName(11))
println(getProvinceName(42))
println(getProvinceName(12))
}
def getProvinceName(case:Int):String = {
code match{
case 42 =>"湖北"
case 11 =>"北京"
case _ => "未知"
}
}
}
package matchcase
object matchcase02 {
def main(args:Array[String]): Unit = {
val xiaohong = (100,100,100)
val xiaoming = (89,98)
getScore(xiaohong)
getScore(xiaoming)
getScore((1,2,3,4))
}
def getScore(score:Any):Unit = {
score match{
case(a,b,c)=>println("元组中有三个元素:a="+a+"b="+b+"c="+c)
case(a,b)=>println("元组中有两个元素:a="+a+"b="+b)
case _ =>println("未知")
}
}
}
匹配变量类型
package matchcase
object matchcase03 {
def main(args:Array[String]): Unit = {
testType(1)
testType(1.1)
testType("1")
}
def testType(i:Any):Unit = {
i match {
case x:Int =>println("当前变量是:Int")
case x:Double => println("当前变量是:Double")
case _ => println("未知")
}
}
}
样例类及其属性
package matchcase
object matchcase05 {
case class Circle(radius:Double)
case class Rectangle(width:Double,height:Double)
def getArea(obj:Any):Unit = {
obj match{
case Circle(radius)=>println("圆形的面积是:"+radius * radius * 3.14)
case Rectangle(width,height)=>println("矩形的面积是:"+width+height)
case _ =>println("未知")
}
}
def main(args:Array[String]): Unit = {
getArea(Circle(2))
getArea(Rectangle(2,3))
getArea("abc")
}
}
变量声明中的模式匹配
package matchcase
object matchcase06 {
def main(args:Array[String]): Unit = {
val arr = Array(1,2,3,4,5)
var a = arr(0)
var b = arr(1)
var c = arr(2)
println("a = "+ a +" b = "+ b +"c = "+ c)
val Array(x,y,z,_*) = arr
println("x = " + x +"y = " + y + " z = " + z)
}
}
守卫
case 模式 if 条件 => 执行的事情
package matchcase
object matchcase07 {
def main(args:Array[String]):Unit = {
val a =11
a match{
case x:Int if a > 10 => println("a 是大于10的Int")
case _ => println("a is not Int")
}
}
}
